Vauban-style fortresses had many elements. The main walls were often surrounded by outer defensive works to provide added protection. These usually consisted of a Glacis which were sloped earthworks, backed by masonry. There were also smaller triangular shaped bastions (sometimes called Ravelins) to provide extra flanking fire. PaperTerrain's outer works kits allow you to add these elements to your 4-sided and 5-sided forts as well as Vauban City Walls. The 6mm scale kits include 15 angled Glacis pieces, 45 connector pieces, and 5 small Ravelins.  The kits are available in either brick or stone finishes to match the fort kits.